Part Type
Aluminum Fixture Plates & Workholding
Flat, drilled on grid, and dead repeatable.
An aluminum fixture plate is a flat plate drilled on a grid of tapped and dowel holes so it locates and clamps a part the same way every cycle, whether it bolts to your part or sits as a sub-plate on the machine table. Cast tooling plate (MIC-6 or Alca) is stress-relieved so it stays flat, and the dowel holes get reamed to a tight class so parts repeat to within thousandths instead of being eyeballed each time. Send a STEP file and a PDF through the quote form and a real person sends back price, material, and lead time in 24-48 hours, with no minimum order.
Updated June 2026
What a fixture plate actually is
At its simplest a fixture plate is a flat slab of aluminum with a pattern of holes in it: tapped holes on a grid for clamps and toe stops, reamed dowel holes for repeatable location, and counterbored slots where bolts pass through to the part underneath. A sub-plate is the version that bolts to the machine table and gives you a clean tapped grid to build off, so you stop drilling into the table itself. A locating fixture goes further and holds one specific part: edge stops, pins, and clamps positioned so the operator drops the part in one way and it sits the same way every time.
The whole point is repeatability. When a part loads against two reamed dowel pins and a flat datum face, it lands in the same spot every cycle, so the program stays true and parts come off interchangeable. If you are not sure what grid you need, the team can design the plate from your part and your process, not just cut to a print you have to draw first.
Flatness and material: cast tooling plate vs 6061
Material choice comes down to how flat the plate has to stay. Cast aluminum tooling plate (MIC-6, Alca, or generic cast tool plate) is pre-stress-relieved, so it arrives flat and stays flat after the holes go in, which is what you want in a sub-plate or a precision locating fixture. General-purpose 6061 is the right call for everyday fixtures and anything where a few thousandths of bow will not hurt, and it costs less and takes anodize cleanly.
When flatness or parallelism has to be held to a real number, the plate gets precision ground after machining: blanchard or surface grinding flattens the working face and brings two faces parallel within tenths. That is the move for plates that mate to a granite surface, register against a machine table, or stack with other tooling where error adds up. Call out the flatness you need and it gets ground to suit.
The features that make it repeatable
The features that earn their keep are the ones that control location and clamping. Reamed dowel holes are the big one: held to a tight class (think ±0.0005 in) so a hardened dowel pin presses to a slip fit and the plate registers without slop. The tapped grid sets your clamping options: a common pitch is 1 in or 2 in centers in 1/4-20 or 3/8-16, which lines up with off-the-shelf clamps, toe stops, and strap kits. Counterbored clamp slots let you slide and lock hold-downs anywhere along a line.
Edge stops and locating pins set where the part sits, and how the plate gets clamped (vises, soft jaws cut to the part profile, or a vacuum fixture for thin work) sets how it holds. A vacuum plate suits sheet, gaskets, and parts too thin to clamp without bowing. Most of this runs through CNC milling, where the grid, pockets, and dowel bores all get cut in one setup so they stay true to each other.
Build to your print, or from your process
Two ways in. If you already have the fixture modeled, send the STEP and a PDF that calls out the dowel-hole class, the tapped grid, and any flatness requirement, and it gets cut to print. If you have a part and a process but no fixture drawing yet, describe how the part needs to be held and what operation runs on it, and the team can design the plate around it: where the pins go, which faces clamp, and how the operator loads it. This is everyday work for custom machinery builders.
Replacing a fixture you already own works the same way. A worn or one-off plate can be reverse engineered from the physical part into a clean model, then improved where it makes sense (better dowel spacing, a flatter datum) before it gets remade. One plate or a matched set for a cell, with no minimum.
Questions
Before you send a job.
01 What is the difference between a tooling plate and a 6061 plate?
Cast tooling plate (MIC-6, Alca) is pre-stress-relieved, so it arrives flat and stays flat after machining, which matters for sub-plates and precision locating fixtures. 6061 is the general-purpose pick for everyday fixtures where a little bow is fine, and it costs less and anodizes well. Tell the team how flat the plate has to stay and the right material follows from there.
02 How tight can you hold the dowel holes for repeatable location?
Reamed dowel holes are held to a tight class, around ±0.0005 in, so a hardened dowel pin presses to a slip fit and the plate registers without slop. That is what makes a part land in the same spot every cycle. General dimensions on the plate run to ±0.005 in, since only the locating features need the tight numbers.
03 Can you hold a flatness number on the plate?
Yes. When flatness or parallelism has to hit a real spec, the plate is precision ground after machining: blanchard or surface grinding flattens the working face and brings two faces parallel within tenths. Call out the flatness on the print and it gets ground to suit. As-milled is fine when no tight number is required.
04 I have a part but no fixture drawing. Can you still build it?
Yes. Describe how the part needs to be held and what operation runs on it, and the team can design the plate around it: dowel and pin locations, which faces clamp, the tapped grid, and how the operator loads it. You do not need to draw the fixture first. If you do have a model, send the STEP and PDF and it gets cut to print instead.
05 Can you copy or improve a fixture plate I already own?
Yes. A worn or one-off plate can be reverse engineered from the physical part into a clean model, then improved where it helps (better dowel spacing, a deeper clamp slot, a flatter datum) before it gets remade. One replacement plate or a matched set for a cell both work, with no minimum order.
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